Section 11.2 - Areas of Regular Polygons
*Watch this video to give you a better grasp of the concepts listed below.*
Example 1:
Find the area of an equilateral triangle with side length of 8.
Let's discover a new formula:
Thm 11.3 - Area of an Equilateral Triangle
The area of an equilateral triangle is:
Example 2:
Find the area of an equilateral triangle whose perimeter is 12 inches.
* center and radius of the polygon
are the center and radius of the
circumscribed circle.
* apothem:
* central angle of a regular polygon:
To find the measure of a central angle:
Thm 11.4 - Area of a Regular Polygon
The area of a regular n-gon with side length s is half the product of the apothem a and the
perimeter P, so:
Example 3:
Example 4: